When Bacteria Is a Good Thing: 10 Ways Probiotics and Prebiotics Can Change Your Life

In modern Western society, say the word “bacteria” and alarm bells go off. Germs! Disease! Danger! Modern society seems bent on viewing the microbial world with a combination of fear and disgust. The truth is, though, for the most part, microbes, those tiny single-celled organisms too small to see with the naked eye, are our friends—at least, the ones that live inside our gut and on the surface of our skin. Together, those tiny critters are known as the microbiome, and there are a lot of them. For every single human cell in your body, there are 10 microbes to match. A hundred trillion microbes. Three to six pounds of your total body weight consists of microbes. "The idea that we're more microbe than mammal is as or more profound than the theory of evolution," anthropologist Jeff Leach, of the American Gut Project, an effort to genetically map the microbiome, told Men’s Journal Magazine.

We would literally die without the gut and surface bacteria that populate our bodies. They are our first line of protection against disease. Humans have evolved in concert with these microbes; we are co-dependent. While we are the captains of the ship, the microbes are the loyal foot soldiers. They communicate with our immune systems and battle enemy microbes. Yet we seem obsessed with destroying the microbiome with antibacterial soaps and gels and shampoos and antiperspirants and antibiotics that kill the good along with the bad. A 2014 study found that the microbiome of modern man is a third less diverse than that of our ancestors. We continue on this path at our own risk. Microbiologist Martin Blaser of New York University suspects that the rise of new and deadly diseases in the past few decades, as well as the increase in obesity, asthma, diabetes, and auto-immune conditions, has coincided with the attacks on the friendly bacteria that live with us. Even depression may be linked to a decimated microbiome.

When we are told to eat lots of fiber in our diet, it’s commonly believed that this is to ensure we have regular bowel movements. While true, there may be a more important reason. While we ourselves cannot digest fiber, the friendly bacteria in our guts can. They feed on dietary fiber, thrive on it, and excrete wastes that maintain an acidic environment in the gut. This acidity is decidedly unfriendly to the bad-guy microbes that make us ill. When the acidity level in the gut is disturbed, the pH level moves to the other end of the scale, becoming more alkaline. In an alkaline gut, bad things happen. Dangerous microbes thrive in alkalinity, which can result in fatigue and mental fogginess. An alkaline gut environment can also make the colon walls more permeable, resulting in bacteria seeping into the bloodstream. This is referred to as “leaky gut syndrome,” and can cause inflammation, which many scientists today believe is the culprit behind conditions like obesity, heart disease and even cancer.

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Eating foods that feed our existing gut bacteria is known as prebiotics. That is, we eat foods like fresh fruits and vegetables that our microbial friends thrive on.

Adding new or additional bacteria into our systems, on the other hand, is known as probiotics. Probiotics are fermented foods that contain some of the healthful bacteria that already populate our bodies. Among the probiotic foods we commonly consume are sauerkraut, kimchi, kombucha, kefir, and of course, yogurt.

It’s pretty hard to come across any advertising for yogurt that doesn’t extoll the miracle of the healthful effects of probiotics, but as with all things corporate, beware. There are hundreds or even thousands of different strains of bacteria in your gut. Yogurt typically contains just three strains. It certainly doesn’t hurt to eat yogurt and other fermented foods every day, and probably helps…a little bit.

The analogy that University of Pittsburgh gastroenterologist Stephen O’Keefe makes is apt. "There are thousands of species of bacteria in the colon, and they're more like an orchestra," he says. "They play together to come up with a final sound."

How adding another violin to that orchestra will change that sound is, at best, unknown. But the chances are that you won’t even notice the difference in the music.

Here are some of the ways a healthy gut environment makes beautiful music.

Many studies have shown that obese individuals have higher levels of bad bacteria in their gut called Firmicutes, and that thinner people have higher levels of good bacteria called Bacterioidetes. The British Journal of Nutrition published one study showing that when overweight women were given probiotics that included Bacterioidetes in addition to a low-calorie diet, they lost more weight than women on the same diet but with a placebo.

3. Clears skin.

Skin conditions like eczema, psoriasis and acne have been linked to inflammation, which is linked to our immune system, which is, in turn, linked to our gut, where most of our immune system is headquartered (70-80% of immune cells are in the gut). A study from the National Institutes of Health showed that the immune system helped choose which microbes lived on the skin’s surface, and that different microbes resided on the skin of people with distressed immune systems vs. individuals with healthy immune systems. Preliminary studies seem to indicate that a balanced microbiome can help solve these pesky skin diseases.

4. Helps prevent colds.

A healthy immune system will, in many cases, fight off a cold, and the key to a healthy immune system is a healthy microbiome. An analytical study published in the Korean Journal of Family Medicine found that probiotics may aid in the prevention of a cold.

5. Aids in vaginal health.

A woman’s vagina is naturally acidic, and a healthy and balanced microbiome helps keep it that way. The acidic environment helps ward off microbes that would otherwise lead to vaginal infections.

6. Wards off depression.

The gut literally, through a biochemical connection, communicates with the brain. A review published in the Journal of Agricultural and Food Chemistry made a strong case that the gut-brain axis plays a large part in influencing our cognitive health. In fact, 95% of serotonin, the happiness-producing hormone, is produced and stored in the gut. Some studies have shown that feeding probiotics to mice in stressful situations reduced their level of stress hormones and subsequent stress-related behaviors.

7. Protects from pathogens.

Disease-causing microbes, such as those introduced by mishandled food, dirty water or dirty hands, can lead to minor illness like food poisoning, or major illnesses like tuberculosis. A study in the journal Nature Immunology showed that a healthy gut environment could prevent these dangerous pathogens from colonizing in your gut.

8. Controls your appetite.

Gut bacteria called Helicobacter pylori can alter the level of a hormone called ghrelin, which inhibits hunger, according to a New York University study. The overuse of antibiotics, as well as a diet high in processed and refined foods, which negatively affects our gut bacteria, can lower the levels of Helicobacter pylori and increase our desire to chow down.

9. Lowers risk of heart attack.

A study showed that patients with a heart disease precursor called hypertriglyceridemia, after they were given a probiotic regimen for 12 weeks, showed a marked decrease in their triglyceride level, as well as improvements in other risk factors for a heart attack.

10. Aids in proper brain function.

A study out of University College Cork opened a window into how the gut may directly affect brain function. The study showed that an unbalanced gut environment could lead to a breakdown in the gene responsible for producing myelin, which is the nerve cell coating that helps insulate the electrical impulses that nerve cells use to communicate. Such a myelin breakdown is a major symptom of multiple sclerosis, a disease that often results in tremors, muscle weakness, vision loss, and other severe symptoms, including eventual death. The study may lay the groundwork for treatments of MS, and may conversely indicate the importance of a healthy microbiome for optimum brain function.

While yogurt and other probiotic foods and supplements are useful, the best way to build up a healthy bacterial environment is through eating a healthy, balanced diet high in fresh fruits and vegetables, low or moderate meat consumption, and limits on sugar intake. Additionally, as with virtually any health issue, get plenty of exercise and adequate sleep. Work with your doctor to formulate safe and effective ways to build up optimum gut health.

Larry Schwartz is a Brooklyn-based freelance writer with a focus on health, science and American history.